A cluster of New York fans gathered in the rain behind their team’s dugout after the final out and chanted “Let’s go, Mets!” And with a win Wednesday night at Wrigley Field, the Mets will be going to their first World Series in 15 years.

Rookie Steven Matz gets the start for the Mets in Game 4 while Jason Hammel goes for the Cubs.

“Being up 3-0, we’re very, very fortunate, because the Cubs have played great,” manager Terry Collins said. “We’ve got to come out tomorrow and Steven Matz has got to give us a game.”

After going 0-7 against the Cubs during the regular season, New York is overpowering them with their arms and bats.

Yoenis Cespedes and David Wright each had three hits for the Mets. Cespedes scored the go-ahead run on a two-out wild pitch by Trevor Cahill on a strikeout of Michael Conforto in the sixth inning.

Murphy tied the mark set by Houston’s Carlos Beltran in 2004 with his drive off Kyle Hendricks in the third.

DeGrom followed up dominant starts by Matt Harvey and Noah Syndergaard in New York with one of his own. The NL Rookie of the Year held the Cubs’ big bats to just two runs and four hits. He struck out seven, walked one and retired his final 11 batters.

The righty with the flowing hair improved to 3-0 in his first postseason, with all of the wins coming on the road.

Kyle Schwarber had the towel-waving crowd shaking 101-year old Wrigley Field to its foundation in the first inning with his club-record fifth homer of the postseason. Jorge Soler also had them roaring with his solo drive in the fourth. But manager Joe Maddon’s Cubs have just five runs in this series.

Barring an epic comeback, a World Series drought that dates to 1908 will continue. Only one other team has won a playoff series after dropping the first three games.

Theo Epstein’s Red Sox came back against the New York Yankees in the 2004 AL Championship Series and ultimately ended one long championship curse. Now, the team he constructed in Chicago, that stirred the imaginations of long-suffering fans, finds itself in a similar spot.

“Of course you think about those things, you think about the parallels, think about the fact that that happened against a New York team,” Maddon said. “We think about all that stuff, but it’s up to us to go out and play and execute.”

Cespedes broke a 2-all tie when he led off the sixth with a single against Cahill and scored from third with two out as Conforto swung at a 2-2 pitch in the dirt. The ball rolled to the backstop, allowing the runner to reach first and extending the inning.

Conforto was forced to stay at third when Wilmer Flores’ drive rolled to the ivy in right field was called a ground-rule double. That drew a heated argument from Collins, who came back out to protest some more after he returned to the dugout.

The Mets added two more runs in the seventh on an RBI single by Cespedes and groundout by Lucas Duda off Justin Grimm that made it 5-2.

Hendricks went four innings for Chicago, allowing two runs and five hits.

Never before had the Cubs played this late on the calendar at Wrigley Field. And they did not start this one on a smooth note.

Singer Wayne Messmer had to deal with a faulty microphone before delivering his rendition of “The Star-Spangled Banner.”

The Cubs quickly fell behind 1-0 when Wright singled and scored on Cespedes’ two-out double in the first. But Schwarber brought the crowd back in a big way in the bottom half when he drove a 3-2 fastball the opposite way to left-center for a solo homer.

It wasn’t quite as impressive as the shot he hit to the top of the right-field videoboard that helped knock out St. Louis in Game 4 of the NLDS. That ball got encased by the Cubs where it settled.

This one probably won’t. But still, with his fifth home run of this postseason, Schwarber broke the franchise record set by Alex Gonzalez and Aramis Ramirez in 2003.

Murphy, who connected 14 times during the regular season, made it 2-1 in the third when he drove a 2-1 sinker from Hendricks out to center. Besides tying Beltran’s record, he also set a Mets mark with his sixth postseason homer.

Soler, who came in batting .455 in the playoffs, tied it in the fourth when he drove his third homer of the postseason to right-center.

TRAINER’S ROOM

Mets: Collins said RHP Matt Harvey was feeling “a lot better” and thinks his ace will be ready for Game 5, if necessary. Harvey was struck near his pitching shoulder by a comebacker in the series opener, leading to some swelling.

UP NEXT

Mets: Matz looks to rebound from a loss to the Los Angeles Dodgers in Game 4 of the NL Division Series against the Dodgers. The rookie will also be making his first appearance at Wrigley Field — and his first against the Cubs.

Cubs: After tossing three innings in the clinching Game 4 of the NLDS against St. Louis, Hammel will try to extend the season.